This invention relates to floor cleaning pads used to clean hard surface floors such as wood or vinyl. It more particularly relates to such floor cleaning pads formed of non-woven webs and which are used on the present generation of super or ultra high speed flooring machines which rotate at speeds greater than 1000 revolutions per minute.
In the past it was known to make one-quarter inch floor cleaning pads such as has been made by 3M Corporation for a number of years. The next development of floor cleaning pads was to take the pads and glue them together, then roll them into jelly-donut shapes and cut them into one-inch thick members. However, these pads tended to unravel or spin apart. The so-called garnett method has been used primarily in Italy and two layers of mechanically-layered fibers are glued directly together according to this method. Each of these layers, however, due to the manufacturing technique had differential strengths and experienced the same problems as air-layering as discussed next.
The next development in floor cleaning pads was the so-called air-layered non-woven process, such as is described in U.S. Pat. No. 4,162,344, the contents of which are incorporated by reference in their entirety. This is a method of randomly distributing the non-woven fibers, air layering them, then spraying them with a resin and binder, and cutting them to size. However, this method results in the bottom layer of the air-layered web having a shingled effect wherein the surface fibers are at least partially aligned. This shingling tends to weaken the surface and also to present an undesirable appearance. The opposite surface whose fibers are randomly distributed is the preferred outer cleaning surface. Additonally, these pads have perpendicular longitudinal directions of differential strength. This differential strength was generally of no significant consequence until the recent developments of the super high speed flooring machines.
The old flooring machines were designed to rotate at 175 revolutions per minute. This generation was followed by the 325 machines, the so-called high speed machines. The next jump was to the 1000 rpm machines, the super high speed machines. These are not used for stripping or scrubbing where water is involved as the water is thrown every which way. However, they are very good for buffing or spray buffing or recoating and finishing. In other words, they are used just to maintain the floor. The next development in the machines was the 1500 rpm machine, which was followed by the 2500 propane machine which had its self-contained propane tanks and did not need an electric cord. The next development was the 2000 rpm electric motor machines. These last three machines are very quick and good for maintaining a high gloss, or wet look which is preferred in most public facilities. The history of floor care machines is set forth in "The Road to Ultra High Speed Buffing: Propane Buffers Boost Speeds to Over 2,000 RPM", CM Cleaning Management Magazine, April 1984, page 65, the contents of which are hereby incorporated by reference in their entirety.
With the development of these super high speed machines, the differential in the strengths of the floor pads has caused a number of problems. When the floor pads are subjected to these very high spinning centrifugal forces the pads tend to elongate in their weaker direction. This causes an "ovaling" of the pads and, when the pad hits any object on the floor, the ovaled portion will tear and shred. These pads will last only an average of 2 to 6 hours at these new speeds. If it does not hit anything it will eventually spread and shred. Additionally, the ovaling will cause the pad to expand towards the fiberglass housing portion of the floor machine and impact it thereby tearing the pad. Additionally, when the pads elongate or oval, the flooring machines can vibrate or wobble. Also, if the pad totally shreds, some flooring machines will then impact the floor and mar or burn it.
Janitorial services often are locked (for security purposes) in the building at the beginning of the night to clean the floors, restrooms, and so forth and then let out in the morning. If the janitoral services unexpectedly run out of the floor cleaning pads due for example to their tearing or shredding, the workers are unable to leave the building to get new pads and thus cannot clean the floors that night.